This is a discussion on Reduced recoil loads are really reduced power/energy - whether that's good or bad.... within the Defensive Rifles & Shotgun Discussion forums, part of the Related Topics category; This is a follow up on a thread I started about reduced recoil 00 pellets having the same energy as many .380 loads and I ...

This is a follow up on a thread I started about reduced recoil 00 pellets having the same energy as many .380 loads and I wanted to just add some awareness about reduced recoil loads. I'm in no way saying they shouldn't be used - that's entirely up to you. All I want to accomplish here is to make sure we are accurately aware of what low recoil loads actually are.

I think before going on, I'd like to address a trend I see all over the internet. The vast majority of posters that refer to the effectiveness of a particular load only concern themselves with the pattern the load produces. That's all - the effectiveness of the round as a man stopper is based on pattern alone.

The assumption is that if the pattern is good, the energy will be there. However, there is some reason to question the validity of that assumption. Low or reduced power rounds, advantageously marketed as low recoil, may not hold up energy-wise at 25 yards that most pattern-only based evaluators set for 00 buck. Sure, the pattern can look really good, but does it deliver the energy/momentum required for adequate penetration you are assuming it will?

Actually, none of the following matters if street results show reduced power loads effective at the ranges we are considering. However, reports from the street do raise doubt. We have seen two reports of failures of Federal 132 00 reduced power loads from the street in real-world shootings.

One report was posted in my other thread by a police officer that has seen numerous failures on large dogs and people.

Another report revealed that at 40 yards, and I agree that's stretching the range a bit, but that same load wouldn't even penetrate a 'cheap leather jacket'. Again, 40 yards does push the range, but that was those officers' reality. They were loaded with low power and it didn't do the job. If they had had full power loads we might have seen an entirely different result. Plus, many a deer has been taken with full power 00 at about the 40 yard range and apparently the full power penetrated the deer's leather jacket.

Again, it is not my intent to condemn low power loads, but to explain exactly what they are, how they work, and why the effective range may need to be adjusted back from the generally accepted range of 25 yards to 19 yards.

Low recoil is actually low power loads - nothing more. So why are they called low recoil? Who would want to shoot a reduced power load if they could shoot a reduced recoil load? Unfortunately, there are no shortcuts or magic to reducing recoil produced by rounds. There are only three ways to reduce recoil via the round itself, reduce the mass, reduce the velocity, or both. Here's a comparison to clarify that:

A 12 ga full power load launches 9 00 pellets from the muzzle at 1325 fps. That produces an energy of 1890 ft-lbs. A popular reduced power load is Federal LE or PD 132 00 which also consists of 9 00 pellets, but they reduce the muzzle velocity to 1145 fps which yields a muzzle energy of 1415 ft-lbs. That's a difference of 479 ft-lbs. How much of a difference is that?

Well, 1890 ft-lbs is 34% more muzzle energy than 1415 ft-lbs. IOW, the muzzle energy of a reduced power load is 75% of the full power load. In fractions, a reduced power load has 3/4 the energy, at the muzzle, of a full power load. But, there's nothing wrong with shooting a load that's 3/4 of a full power load as long as we keep it within its effective range.

There are three characteristics to be aware of: Energy delivered, pattern, and penetration. When I discussed this in the other thread, I lost some folks and it took a long time to get everything clarified and I want to avoid that this time, so I'm gonna use two examples to illustrate the principles involved.

I'm going to take patterning as a given and assume the pattern is fine. We have to understand why individual pellet energy is significant and that in one case the pellets' energy that strikes a target adds and in another case they act totally as stand alone projectiles. This is where I lost some people in the other thread; they could not see the significance or relevance individual pellet energy. Let's start with the additive effect of pellets on a target.

Let's say we set a steel plate to fall with a 9mm, 115 gn, 1150 fps bullet striking the upper half of the plate. So we tune our adjustment screw and shoot iteratively until it's adjusted properly. Now what would happen if we shot the plate with a bullet that weighted 54 gns, less than half of the 115 gn 9mm, with a velocity of 1145 fps - would it knock the plate over? No, it's not up to a 9mm 115 gn bullet ballistics the plate is adjusted to. But a single 00 pellet is exactly 54 gns at approximately the same velocity. Now to illustrate the additive effect.

Next we consider two 54 gn pellets hitting the plate, will that knock the plate over? Yes, because the combined weight, velocity, and hence energy of two pellets nearly matches the ballistics of one 9mm the plate is tuned to.

So what do we deduce from this? Well, it takes two low power 00 pellets to equal the energy and momentum of a single 115 gn 9mm bullet. That's for impact or shock, but what about penetration? Let's look at that next.

Energy and mass of the bullet is what drives it into the medium, regardless of what the medium is. In the case of the steel plate, penetration was not an issue at all. That example really illustrates the conservation of momentum and that the energy and momentum of the pellets are additive in that case. Now we will replace the plate with ballistic gel. In this case we will be looking at penetration and the stand alone implications of the energy of the individual pellet.

Let's start slow. Will a 54 gn, 00 pellet penetrate as deeply as one 115 gn, 9mm round with the same velocity? No, it won't, theoretically, since it has half the mass, it has half the momentum and energy, it should penetrate about half as far as the 9mm.

Let's say we hit the gel with two 00 pellets and they are separated by 2 inches. That's just an arbitrary distance, it's only used to help with the visualization. It simply eliminates any stacking effect. That's justified because at 25 yards there is little chance of stacking. The question is will these two pellets penetrate deeper than the single pellet in the previous example? No, they won't, why? Because the only thing driving the pellet is the energy and momentum of the pellet itself - it gets no help from the other pellet.

Now we jump - what if 9 pellets hit the gel and there is no stacking? Do all of them some how magically penetrate deeper? No, there's no way any of the pellets can help each other. There can be some path intersections, but is that something we want to bet our lives on?

However, what is the total energy delivered to the target? It is the sum of the individual pellet energies. So we have additive impact, but stand alone penetration effects.

What this all boils down to is we can have a lot of energy delivered due to the additive effect. But even with all that energy delivered, we can still have poor penetration due to the stand alone effect of individual pellets.

I guess the bottom line is, understand what reduced recoil really is. Reduced recoil is not produced, low power is produced and it results in reduced recoil. Reduced recoil is a side effect of reduced power, not the other way around.

And, think about this. If full power 00 is effective to 25 yards, what should a load that is 3/4 of a full power load be effective to? How about 3/4 of the range? Or, 19 yards.

Just be careful you're not expecting full power load performance from reduced power loads. If it's enough for your purposes, then fine. But if you're pushing it to full power expectations it would be prudent to consider a full power load instead of the low power.

Or if you are expecting effective barrier penetration, keep in mind that full power isn't all that great of a barrier penetrator to start with, depending on what the barrier actually is. It was a cheap leather jacket in one instance.

To illustrate the relevance of such considerations, I'll leave you with this problem: If you have a choice of two loads, and they both have the same muzzle velocity and one load is 8 00 pellets and one is 9 00 pellets, which would produce the most recoil and by how much, and which would have more penetration capability?

Good post. I do have a couple potential issues with the stacking concept - wanna talk about it now or is that coming up in another post. Here's the match: What exactly are the claims about the benefits of stacking? I understand the concept, but don't know what the perceived benefits are.

Good post. I do have a couple potential issues with the stacking concept - wanna talk about it now or is that coming up in another post. Here's the match: What exactly are the claims about the benefits of stacking? I understand the concept, but don't know what the perceived benefits are.

The prob child

LOL - Hey ndrgr,

Well, the short answer would be that stacking increases depth of penetration significantly for the pellets that stack. Now, the long answer.

There are two phenomenon that can occur with buckshot when they hit the threat/gel. One is stacking, and the other is intersecting tracks in the medium.

Starting with the latter, intersecting tracks, this can purportedly occur because the buckshot pellets are not stabilized like a rifled projectile. The thinking is, and probably demonstrable in gel, that a pellet(s) may curve in the medium rather than travel in a straight line and another pellet may travel through that curved path. Well, that offers less resistance to the other pellet so it could penetrate a bit deeper. However, to me, that's not something I would count on.

The other phenomenon is stacking. In its simplest form, it means one (or more) pellet(s) is perfectly aligned right behind another(s) in the same trajectory when they hit the medium. This is quite likely to occur BEFORE the pellets spread, quite unlikely to happen after the pellets spread significantly. The theory is that IF two pellets (or more) enter the very same point, one on top of the other, i.e. stacked, that the pellets add in both energy and momentum which will increase penetration significantly compared to a single pellet.

When all the pellets are together or just fractions of an inch apart, I can kinda see stacking could occur, at least partial stacking. I think the chances of any two (or more) pellets stacking precisely in line with each other is highly improbable.

Then, there could be parallel stacking where two pellets are beside each and in contact with each when they hit. That's harder to predict, but I would think there would be some increase in penetration. But again, at ranges where we have 9 pellet spreads of like 2 - 3 inches across, I really don't think we can count on much benefit from any kind of stacking.

Of course as pellet size goes down and pellet count goes up, there might be more of a chance of stacking and intersecting to occur, but generally, at least what I've seen, the more pellets there are, the wider the pattern so there again the greater spread reduces the chance of stacking.

That's what I thought it was. However, like you said, the chances of pellets actually stacking is slim and it ignores a few things. First, at the point of impact, the front pellet will slow first, due to encountering a denser mass, then as the two pellets collide they will deform, which also absorbs energy/velocity. Second, the rear pellet will not be able to accelerate the first pellet back to the original velocity as it's means of propulsion was left at the other end of the barrel. Third, the chances of the pellets colliding in perfect alignment to further penetration is slim to none, thus sending both pellets in directions diagonally to the original path (like in billiards or NASCAR) making a possibly long enough path, but in the wrong direction. Buckshot doesn't start off perfectly aligned in a shell, why would anyone suggest it magically strikes the target as such? and where do they think the extra acceleration is coming from? As soon as there is any spread in the load at all, what happens is as pellets fly through the air, the pellets in front encounter more air resistance, are slowed, and pushed to the side (not/never being perfectly aligned) by the rear pellets which were drafting off of them.

As for parallel stacking, we're talking two round objects pushing their way through a solid. As they do this their leading edges are pushing tissue into each other's paths, thus both deflecting each other and slowing each other like two boats running parallel through the water in each other's wakes.

...First, at the point of impact, the front pellet will slow first, due to encountering a denser mass, then as the two pellets collide they will deform, which also absorbs energy/velocity.

True if they are not in contact, but as soon as the leading pellet hits restriction, it will slow down and the trailing pellet will catch up and make contact. There could be a small amount of deformation, but considering the two pellets were traveling a pretty much the same speed, and very close together the collision would be mild - why are we discussing this . I doubt much energy would be expended in such a collision, but that's of little consequence I think.

Originally Posted by nedrgr21

...Second, the rear pellet will not be able to accelerate the first pellet back to the original velocity as it's means of propulsion was left at the other end of the barrel.

Consider this: a cue ball strikes a stationary ball perfectly through the centerline of the ball, what happens? The stationary ball acquires the momentum of the cue ball and accelerates. So the ball hit is accelerated faster than it's initial velocity which was zero. What happens to the cue ball? If it were not for the spin due to rolling across the table (assume no 'english' was involved) the cue ball would stop completely. However the cue ball wouldn't stop because not only does it have linear kinetic energy, it has angular kinetic energy which would not transfer efficiently to the struck ball so the cue ball would in fact continue to roll due to an proportionally to all it has left - angular momentum.

Now consider the cue ball strikes a ball that is in motion at almost the same velocity as the cue ball, what happens? Again the conservation of momentum. The difference in velocities creates a transfer of momentum proportional to the difference in speed. In any event, on a pool table when this very thing happens, the struck ball runs away from the cue ball because momentum has been transferred to it. Soooo.....

In the case of two stacked pellets the same thing could happen. Energy and momentum from the second transfers some energy and momentum from the trailing pellet. More likely the two pellets come in contact and travel together as a heavier projectile.

The thing here is that only the frontal area of one pellet is having to penetrate the resistance with the other pellet either pushing or bumping it every time the front pellet slows down. Energy and momentum from both pellets have to be absorbed to stop the pellets. Since they both are only resisted by one frontal area, they would come close to penetrating twice as much as a single pellet, minus the energy lost through any deformation.

Originally Posted by nedrgr21

...Third, the chances of the pellets colliding in perfect alignment to further penetration is slim to none, thus sending both pellets in directions diagonally to the original path (like in billiards or NASCAR) making a possibly long enough path, but in the wrong direction.

Well that's certainly true - without a doubt up to the part about 'wrong' direction. If it deflects a pellet toward the heart, it helps; if it deflects a pellet away from the heart that would have hit the heart if not deflected then that might be considered the wrong direction.

Originally Posted by nedrgr21

...Buckshot doesn't start off perfectly aligned in a shell, why would anyone suggest it magically strikes the target as such?

Well, I think, emphasize think here, even if they were perfectly aligned in the shell, I doubt they would remain that way. As I said in my previous post, stacking is very unlikely.

Originally Posted by nedrgr21

...and where do they think the extra acceleration is coming from?

It isn't a matter of extra acceleration, it's a matter of the pair not decelerating at the same rate as one pellet. Remember all the energy and momentum from two pellets have to be absorbed before the pellets will stop and they're in the same wound channel. But again, stacking is a fluke, perhaps only occurs in theory so it's really not anything to rely on.

Originally Posted by nedrgr21

...As for parallel stacking, we're talking two round objects pushing their way through a solid. As they do this their leading edges are pushing tissue into each other's paths, thus both deflecting each other and slowing each other like two boats running parallel through the water in each other's wakes.

True, I wouldn't count on that either.

Originally Posted by nedrgr21

...Who comes up with this stuff?

I think it was you and I, and I hope we don't have to discuss this anymore - I'm having to think too much

And stacking is such an unlikely thing that it's off no consequence.

For the sake of not boring readers into submission, let's move the highly theoretical stuff to PM's.

...First, at the point of impact, the front pellet will slow first, due to encountering a denser mass, then as the two pellets collide they will deform, which also absorbs energy/velocity.

True if they are not in contact, but as soon as the leading pellet hits restriction, it will slow down and the trailing pellet will catch up and make contact. There could be a small amount of deformation, but considering the two pellets were traveling a pretty much the same speed, and very close together the collision would be mild - why are we discussing this . I doubt much energy would be expended in such a collision, but that's of little consequence I think.

Originally Posted by nedrgr21

...Second, the rear pellet will not be able to accelerate the first pellet back to the original velocity as it's means of propulsion was left at the other end of the barrel.

Consider this: a cue ball strikes a stationary ball perfectly through the centerline of the ball, what happens? The stationary ball acquires the momentum of the cue ball and accelerates. So the ball hit is accelerated faster than it's initial velocity which was zero. What happens to the cue ball? In a perfect strike, it would stop.

Now consider the cue ball strikes a ball that is in motion at almost the same velocity as the cue ball, what happens? Again the conservation of momentum. The difference in velocities creates a transfer of momentum proportional to the difference in speed. In any event, on a pool table when this very thing happens, the struck ball runs away from the cue ball because momentum has been transferred to it. Soooo.....

In the case of two stacked pellets the same thing could happen. Energy and momentum from the second transfers some energy and momentum from the trailing pellet. More likely the two pellets come in contact and travel together as a heavier projectile.

The thing here is that only the frontal area of one pellet is having to penetrate the resistance with the other pellet either pushing or bumping it every time the front pellet slows down. Energy and momentum from both pellets have to be absorbed to stop the pellets. Since they both are only resisted by one frontal area, they would come close to penetrating twice as much as a single pellet, minus the energy lost through any deformation.

Originally Posted by nedrgr21

...Third, the chances of the pellets colliding in perfect alignment to further penetration is slim to none, thus sending both pellets in directions diagonally to the original path (like in billiards or NASCAR) making a possibly long enough path, but in the wrong direction.

Well that's certainly true - without a doubt up to the part about 'wrong' direction. If it deflects a pellet toward the heart, it helps; if it deflects a pellet away from the heart that would have hit the heart if not deflected then that might be considered the wrong direction.

Originally Posted by nedrgr21

...Buckshot doesn't start off perfectly aligned in a shell, why would anyone suggest it magically strikes the target as such?

Well, I think, emphasize think here, even if they were perfectly aligned in the shell, I doubt they would remain that way. As I said in my previous post, stacking is very unlikely.

Originally Posted by nedrgr21

...and where do they think the extra acceleration is coming from?

It isn't a matter of extra acceleration, it's a matter of the pair not decelerating at the same rate as one pellet. Remember all the energy and momentum from two pellets have to be absorbed before the pellets will stop and they're in the same wound channel. But again, stacking is a fluke, perhaps only occurs in theory so it's really not anything to rely on.

Originally Posted by nedrgr21

...As for parallel stacking, we're talking two round objects pushing their way through a solid. As they do this their leading edges are pushing tissue into each other's paths, thus both deflecting each other and slowing each other like two boats running parallel through the water in each other's wakes.

True, I wouldn't count on that either.

Originally Posted by nedrgr21

...Who comes up with this stuff?

I think it was you and I, and I hope we don't have to discuss this anymore - I'm having to think too much

And stacking is such an unlikely thing that it's off no consequence.

For the sake of not boring readers into submission, let's move the highly theoretical stuff to PM's.

Well you brought it up 2/3 through your post and this is the part that gets me started "they would come close to penetrating twice as much as a single pellet, minus the energy lost through any deformation.". I cringe at the thought people think this actually happens and worse yet, count on it to increase penetration. Hey, cool we agree on the end result as a whole lot of perfect conditions, not reproducible even in a lab would have to occur simultaneously.

That 2/3 is that percent irony. The full power is 34% more powerful than the low power, calculated by using the low power as the reference. But low power is 3/4 of the full power using the full power as the reference - crazy percentages!. I had 2/3 but changed it to 3/4. So reduced power is 3/4 the power of full power.

Originally Posted by nedrgr21

...and this is the part that gets me started "they would come close to penetrating twice as much as a single pellet, minus the energy lost through any deformation.". I cringe at the thought people think this actually happens and worse yet, count on it to increase penetration....

Well, if you will allow me to clarify that a bit. What I said was, as you correctly quoted, "...they would come close to penetrating twice as much as a single pellet, minus the energy lost through any deformation." is correct according to theory. What you were commenting on is that people believe that happens. Yeah, it could simply due to the random nature of pellet patterns, especially at close ranges where it would be of no benefit at all if it did. But it is highly improbable to happen even as a partial stacking after the pellets start to spread and should never be depended on.

Originally Posted by nedrgr21

...Hey, cool we agree on the end result as a whole lot of perfect conditions, not reproducible even in a lab would have to occur simultaneously.